I can only speak for the service side as that is the area of Connectwise (CW) I work with primarily.
There is a lot of valuable data collected by CW, the usefulness of it easily determined by the CW customer. I wager that any customer, given they have the talent on hand, could gather enough data from CW to run their operation very well. For this area I would give CW five stars.
Their email connector and the system built around it works very well.
Here are the areas that need improvement:
Reporting is weak. Quite weak actually. While some decent canned reports exist, it appears that CW runs under the philosophy of letting their customers create their own. This has many pros for CW, but they should really offer more.
It is FAR TOO LABORIOUS to perform common heavily used functions: Ticket creation, Time entry, managing attachments, etc. If one counts their mouse clicks as they navigate, you will often find it taking two hands to count the clicks required to perform something as simple as getting a start/end time entered into the system.
CW has greatly improved the UI from where it was two years ago, but they need serious help with the design in terms of what I just mentioned. When working on multiple "hot" items, the UI quickly becomes a hindrance, so much so that you're BP will likely rise by 5-10% because of it.
Cloud Performance: I find it difficult to experience response times less than 4 seconds and frequently see this rise to the range of 10 seconds. By itself this isn't terribly bad, however, (see previous point) add in the extra clicks required to navigate, and I find myself wishing for a 56k modem instead.
All in all it's a solid product. CW is continuing to make improvements according to customer input, and this is a good thing. I can't say we made a poor choice in selecting CW. I just hope they improve these areas.